Cancer management is one particular area where local release of chemical agents for either therapeutic aim or for therapeutic sensitization has important advantages in targeted therapy. Traditionally, therapeutic cancer agents are administered in high concentration throughout the body in order to destroy cancer cells, translating to high toxicity and discomfort for the patient, mainly due to the effects on normal cells.
Two of the most common methods of treating cancer, chemotherapy and radiation therapy, are well known to have detrimental effects on the patient, such as anemia, extreme fatigue, hair loss, infection, memory changes, mouth and throat changes, nausea and vomiting, nerve changes, sexual and fertility changes, and swelling. These side effects arise from chemotherapy because the treatment kills rapidly dividing cells. Although these cells include most cancer cells, they also include cells that naturally divide rapidly, such as those in the digestive tract, hair follicles, and bone marrow. Although radiation therapy side effects are generally more localized, swelling, infertility, skin damage, and changes to the mouth and throat can occur, depending on the area treated. Other cancer treatment methods also are associated with important disadvantages. For example, traditional surgery involves long recovery time and can result in insufficient removal of all cancerous tissue; cryosurgery is limited to specific tumor types and long-term effectiveness has not been established; laser therapy involves extensive doctor training and expensive equipment, and the effects may not last long; and angiogenesis inhibitors may not kill tumors, but merely prevent new growth.
Miniaturized medical procedures are of great interest in cancer treatment, because they allow the precise treatment of cancerous cells with little or no effect on surrounding normal tissue. Furthermore, local release of chemical agents for either therapeutic aim or for therapeutic sensitization has important advantages in targeted cancer therapy. Micro-machined devices, such as micro-cantilevers, are currently used in a variety of different medical applications, such as for blood glucose monitoring, detection of chemical and biological warfare agents, and the detection of diseases and point mutations. Micro-cantilevers, which resemble planks, are commonly about 10-50 micrometers (μm) long and about 1 μm thick, and bend in response to different forces. A typical micro-cantilever may have a plurality of binding sites located on its surface to electively bind to target molecules, such as antibodies, proteins, or nucleic acid strands. The interactions between the binding sites and the target molecules change the mechanical response of the system such as its resonant vibration frequency.
Chemosensitizing drugs are used to make tumor cells more sensitive to chemotherapy, thereby allowing for smaller doses or fewer treatments of chemotherapy and a less severe effect on healthy tissue. Similarly, monoclonal antibodies delivered to cancer cells may also help target treatment. The application of monoclonal antibodies may function to make the cancer cells more visible to the patient's immune system, may block tumor growth factors, may prevent the growth of new blood vessels in the tumor, or may aid in the targeted delivery of radiation to cancer cells.
It would be advantageous to precisely deliver cancer treatment drugs to cancerous cells, and/or to deliver chemosensitizing agents and monoclonal antibodies (either alone or in combination) to aid in the targeting of other cancer treatments such as chemotherapy and radiation. Therefore, what is needed is a device that can store and deliver treatment agents to a target tissue site while minimizing damage to healthy tissue and adverse effects on the patient.